The present invention relates to an apparatus for inspecting the sidewall of a bottle under rotating.
Glass bottles used for filling with liquor, refreshing drink, food or the like must be inspected as to whether there is any defect irrespective of whether they are new ones just manufactured by a bottle marker or old ones recirculated. Portions of a bottle to be inspected include its body or sidewall, bottom, top of mouth and threaded bottle neck. Of defects on the bottle sidewall, defects such as foreign matters or stains may result in a potential problem of food sanitation, and defects such as cracks or voids may result in breakage of the bottle. Thus, it is necessary to correctly detect such defects and remove defective bottles.
However, the sidewall of a bottle may have unevenness of color or thickness. Thus, such unevenness sometimes becomes an obstacle in detecting an actual defect or may be detected erroneously as a defect. In addition, there also arises a problem that because of such unevenness, it becomes difficult to properly set an inspection area or a sensitivity.